Unified communications (“UC”) represents an important component of productivity in contemporary business culture, and its success from company to company can serve as a bellwether indicator of the company's overall management success. An essential feature behind unified communications is the ability to have a single way for reaching an employee.
A headset device typically provides the glue that holds a UC system together. Using his headset, a user may typically access a variety of applications and systems available through his communication network. Communications to the headset are typically facilitated by a dongle of some sort that provides communications between the headset and a device providing network connectivity (e.g., a computer, a mobile phone).
A consumer (or other user) may easily transport a portable Digital Enhanced Cordless Telecommunications (DECT) device, such as a DECT dongle used in UC applications, into a new region where the device's frequency spectrum and/or power output have characteristics that cannot be legally used in the new region.
For example, transporting an EU-compliant DECT unit into North America is typically not permitted. Operating the European Union (EU) device in North America may cause severe problems with other telecommunications systems such as a local mobile telephone network. Assume in this example that a low-power (5 mW) EU-DECT system has been activated within a geography governed by North American telecommunications standards, e.g., a jurisdiction in which a North American cellular telephony network is legally operating. Although the EU-DECT device has relatively low power, the EU-DECT system may nevertheless cause a severe disruption in the quality of service for the portion of the North American system operating in close proximity to the EU-DECT system.
Interference from an EU-DECT unit operated in North America can occur, for example, in the Personal Communications Service (PCS) cellular handset transmit band, which is the PCS cellular base station's receive band. A PCS base station and PCS handsets typically use different frequency bands for transmit and receive, with one system's transmit band being the other system's receive band. The transmit band for a typical EU-DECT unit typically matches the PCS base station's receive band for all of the EU-DECT unit's radio signals. Thus, if the EU-DECT unit is close to a PCS cellular base station, even if the EU-DECT unit is low power, because it is close, the EU-DECT unit can deafen the PCS cellular base station to the transmissions of distant PCS cellular phones.
FIG. 1 illustrates a telecommunications network 100 comprising mobile phones 105-111 and a base station 103 which has come into the proximity of a non-compliant DECT unit 101a. The DECT unit 101a has been designed for communications with a headset 101b. (The DECT unit 101a may comprise a DECT dongle, for example.) The DECT unit 101a has a sufficiently strong power output that in communicating with the headset 101b, the DECT unit 101a subjects the base station 103 to interference. In other words, the DECT unit 101a inadvertently shares the same frequency band with the base station 103. For example, the base station 103 may comprise a PCS base station whose receive band matches the transmit band for the DECT unit 101a. The interference caused by the DECT unit 101a in the receive band of the base station 103 may render the base station 103 unable to receive signals from mobile phones 105-111, and the communications difficulties will increase the farther the mobile phones 105-111 are located from the base station 103. This situation can arise when, for example, an EU-DECT system (e.g., the DECT unit 101a-101b) is improperly brought into and operated in the North American PCS band, thus becoming an “interference emitting” wireless telecommunications system.
An end-user consumer associated with the headset 101b and the DECT unit 101a may not be aware of the interference to the base station 103 in the network 100, and the user is unlikely to be aware that his own unit is responsible for causing the interference. An operator of the network 100 will typically have to identify interfering units, such as the DECT unit 101a, and take overt actions to stop them from interfering with the network 100.
Dongle manufacturers have limited control over the post-sale movement of the portable telecommunications devices they produce and have limited abilities for preventing portable communications devices from being transported into unapproved areas. The only commercially deployed solution to this interference problem (typically caused by DECT-compliant units) has been to label the units (e.g., the DECT units 101a and 101b) according to the national market for which they are intended for operation and/or sold. This approach presumes that consumers will notice the labels and understand the national laws and requirements for any jurisdiction in which they might bring the DECT unit 101b and utilize only approved devices.
The approach above provides a working solution, of sorts, but unfortunately relies upon the end user's powers of observation and desire to do the right thing with no obvious financial or business benefits for compliance. Many consumers do not read the documentation that comes with their units or pay any attention to the warnings placed on their units. Consequently, labeling units for their intended market does not provide a complete solution to this problem. Additionally, given that the consumer's use of his non-compliant device is likely not interrupted, the primary motivation for a consumer to stop using his non-compliant DECT device relies primarily upon the better angels of the user's nature. Given that the cost of these non-compliant DECT devices is typically not trivial, one can assume that at least some consumers will not be willing to give up using their non-compliant devices for the good of an otherwise anonymous community of strangers.
Another proposed solution calls for adding global position system (“GPS”) units into radio-based products to prevent them from being used around installations known for susceptibility to interference, such as military communications equipment and base stations. While many mobile phones include built-in GPS units, most headsets do not, and adding a GPS unit to headset or other telecommunication might significantly increase the price (e.g., double the price) for such devices. Consumers would likely balk at having to pay for GPS units for cordless telephones operating according to standards such as DECT. In short, this proposed solution is economically impractical unless and until the cost of GPS units becomes trivial. The solution also likely has implementation problems due to privacy issues.
Other solutions have proven equally inadequate or inappropriate for providing a robust unified communications system for devices capable of being transported in the proximity of networks where they are not authorized for operation. A simple and robust solution is called for in order to make unified communications more robust, ubiquitous, and compliant with various local, national, and regional laws and regulations.